Normal anionic gap is seen in: March 2009
**Core Concept**
The anionic gap is a calculated value representing the difference between the concentrations of cations and anions in the blood. It is an essential parameter in the diagnosis of various metabolic acid-base disorders.
**Why the Correct Answer is Right**
The anionic gap is calculated by subtracting the sum of the concentrations of chloride (Cl-) and bicarbonate (HCO3-) from the sum of the concentrations of sodium (Na+) and potassium (K+). A normal anionic gap is typically seen in conditions where there is no significant accumulation of unmeasured anions or cations. This is often observed in diabetic ketoacidosis (DKA) due to the accumulation of ketone bodies, which are organic acids. However, the anionic gap in DKA is usually elevated. In contrast, a normal anionic gap is seen in conditions like lactic acidosis, where the anionic gap is not significantly elevated due to the accumulation of lactate.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because diabetic ketoacidosis typically presents with an elevated anionic gap due to the accumulation of ketone bodies.
* **Option B:** This option is incorrect because hyperchloremic metabolic acidosis, often seen in the setting of gastric aspiration or renal tubular acidosis, typically presents with an elevated anionic gap.
* **Option D:** This option is incorrect because uremia, a complication of renal failure, typically presents with an elevated anionic gap due to the accumulation of various organic acids.
**Clinical Pearl / High-Yield Fact**
It is essential to remember that the anionic gap is not a direct measure of acidosis but rather a calculated value that can help diagnose various metabolic acid-base disorders.
**Correct Answer: C. Lactic acidosis.